Compensating means for liquid level indicators



BY K l I i l I I I I I I i I l I I I m\QkwQ\Q J M CRANMER COMPENSATING MEANS FOR LIQUID LEVEL INDICATORS Filed July 2, 1947 Nov. 1, 1949 Patented Nov. 1, 1949 a saszs QQMBENSAZR g Fon LIQUID payer. Q RIM Q Q John Matthias Cranmer, East Providence, R. I., assignor tb Socon'y -Vacuum' Oil Company, In corporated, New York, N. .,-acorporation-of a lication July 2 1947, Serial no. 753,549

entails? (c1. vat- 321i This invention relates generally to level gauges or indicating apparatus, such'as are suitable for use' witlrliquidstorage tanks which employ'floab been proposed for accurately determining the those occasioned by rain can be taken care of by proper drain facilities but loads due to snow, sleet, ice, etc. cannot be coped with so readily.

Therefore, the principal object of the present invention is to overcome the above recited difficulties by providing novel means for accurately and automatically compensating for the occasional loading of a floating roof which actuates a liquid level indicator or gauging means.

Other objects and. advantages of the present invention will become apparent from the following detailed description when considered with the drawings in which the single figure is a schematic illustration of a vertical section of a floatingroof type storage tank showing the present invention applied thereto.

Referring to the drawing in detail a tank I having fluid II therein is provided with a floatin roof I2. Roof I2 comprises a toroidal pontoon I3 the center portion of which is closed by a sheet metal cover plate I4. One or more truss members I5 are provided which extend horizontally across the pontoon I3. If more than one are used then one of them is located near one diameter of the roof. 0n the bottom side at a point intermediate the ends of this truss member, but near the center thereof, there is provided a socket bearing I6 which is adapted to receive a ball carried by one end of a lever IT to form a ball and socket joint. The opposite end of lever I! is pivotally connected to the top of a substantially vertical link I8. The bottom end of link 18 is secured to the approximate c'en' terof thesheet metal plate I4 whereby relative movement between the sheet metal plate Mand the truss member I5, produced by the fleirure'of:

the plate I4, will move the lever II.

' customarily, in order to determine the position of a floating roof'in a tank; one or" more cables or tapes" are fastened to the roof' and around suitably located pulleys to or through a gauge or indicator which will be actuated therebyx The cable or tapeis usually provided with fiduciary marks which'registe'r'with an indicator;

The marks may indicate linear displacement 'of.

thereof or the'qu'antity of fluid in the tank.

The p-resent'invention utilizes conventional appar'atusoutside the tank. This apparatus "is shown schematically'inthe drawings in which the tapes or cables 19 are shown c'oiflizig but of the tank lflan'd overpulleys 20 whicl'i' are rotatably mounted o'n'supp'ortsQ Ithat are fixed to the out side of the tank near its top. The cables or tapes I9 pass downwardly along the sides of the tank and under pulleys 22 which are mounted on supports that are carried by the tank at points near the bottom thereof. The cables or tapes I9 then pass upwardly through gauges or indicators to pulleys 23. After they are brought over pulleys 23 suitable weights 24 are secured to their respective ends.

Those portions of cables or tapes I9 which extend downwardly into the tank II] are passed under pulleys 24 which are carried by suitable supports 25 that are fixed to the pontoon roof I 2. The cables or tapes are then brought together through suitable guides 25 at a point located substantially at the center of the roof. At this point a pair of pulleys 2! are mounted on the truss member I5 by support 28. The cables are joined by bringing them together over the pulleys 21 and down between them, through the truss members I5 to the lever H. The ends of the cables are secured to the lever I! at a selected point intermediate the ends thereof. Therefore any movement of the lever II will produce a longitudinal movement of the cables I9.

In operation when there is no load on the floating roof I2 there will be no flexure of the sheetmetal plate I4 and the indicator will function in the conventional manner to indicate linear displacement of the roof or quantity of liquid in the tank. When the floating roof is loaded, as oocasioned by snow, sleet, ice, etc., complete compensation is effected for roof distortion. The load will produce a downward flexure of the sheet-metal plate I4 causing it to displace more fluid resulting in a lifting of the pontoon. The fiexure of plate I4 creates a relative movement between the plate and truss member I 5. This action takes up some of the length of the cables or tapes I9 through the medium of lever I'I. This take-up in the cables or tapes is regulated by properly selecting the point where the cables or tapes are fastened to the lever IT to just compensate for variations in roof load.

Additionally the amount of fiexure of plate I4 can be magnified to any desired degree by properly selecting the length of lever I I and the point on the lever at which the cables or tapes are secured.

I claim:

1. A liquid level indicator for oil storage tanks that comprises in combination a sheet-metal roof, a toroidal pontoon adapted to float on the liquid in the tank and support the roof, liquid level indicating means located outside of the tank, means associated with said indicating means and connected indirectly to the sheetmetal roof for indicating the level of the roof in the tank, and means interposed between said last means and the roof, operable by the flexure of the roof, for compensating for errors in liquid level indications due to loads, such as snow, sleet, ice, etc., on the roof.

2. A liquid level indicator for oil storage tanks that comprises in combination a sheet-metal roof, a toroidal pontoon adapted to float on the liquid in the tank and support the roof, liquid level indicating means located outside of the tank, means associated with said indicator and connected through linkage to the sheet-metal roof and operable by the flexure of the roof for indicating the level of the roof in the tank, said connecting means comprising means for compensating for errors in liquid level indications that are due to roof distortion occasioned by loads 00- casioned by snow, ice, sleet, etc.

3. A liquid level indicator for oil storage tanks that comprises in combination a sheet-metal roof, a toroidal pontoon adapted to float on the liquid in the tank and support the roof, a horizontal truss member extending across and connecting opposite sides of the pontoon, liquid level indicating means located outside of the tank, means associated with said indicator and connected indirectly to the sheet-metal roof for indicating the level of the roof in the tank, and means interposed between said last means and the roof for compensating for errors in liquid level indications due to loads, such as snow, sleet, ice, etc., on the roof, said last recited means comprising a lever, means for pivotally securing one end of said lever to the truss member, means for pivotally securing the other end of the lever to the sheet-metal roof, and means for connect ing the means associated with said indicator to said lever at a selected point intermediate the ends thereof, whereby relative movement between the truss member and sheet-metal roof will effect a compensation for errors in liquid level indications due to loads on the roof.

JO'HN MATTHIAS CRANMER.

REFERENCES CITED The following references are of record in the file of this patent:

UNIIL D STATES PATENTS Number Name Date 1,988,808 Pierce Jan. 22, 1935 2,086,645 Staber July 13, 1937 2,117,185 Lynskey May 10, 1938 2,237,461 Tokheim Apr. 8, 1941 2,282,772 Wiggins May 12, 1942 

